The objective is to study the human brain with methods developed in ongoing basic laboratory investigation. We have focused on two separate subjects: (1) intracellular potential from "idle" cells (probably glia) in cat cerebral cortex; (2) comparative studies of sensory input to motor cortex in animals and man. In the intracellular studies we have found that idle cells show reversible depolarization during cortical or thalamic stimulation, peripheral physiologic stimulation, during seizure discharge and during spreading depression. Also that the slow depolarization contribute to stimulus bound DC shifts recorded from the cortical surface. In the comparative study of sensory input to motor cortex, evoked response studies have shown that in man the input is less diverse thanthat found in animals, being a predominantly contralateral somesthetic one. These studies have been extended to extracellular unit recording during application of physiologic stimuli. In contrast to the findings inthe studies with evoked responses, cells have been found that can be activated by ipsilateral, as well as contralateral physiologic stimulation. However, the results differ from those found in animals in that the input, thus far, is proving to be only a kinesthetic one, tactile and auditory stimuli being ineffective. Studies are being extended to include the face as well as the hand area. In the intracellular studies, "idle" cells of cat cerebral cortex have been shown to be exquisitely sensitive to potassium. These cells have been shown to undergo hyperpolarization as well as depolarization, both changes being potassium dependent, and not associated with membrane conductance changes.